U.S. Patent Application Ser. No. 940,011, filed Sept. 6, 1978, GEISSLER, now U.S. Pat. No. 4,194,234, assigned to the assignee of the present application, discloses electronic photoflash guns having a holder for a single gas discharge lamp positioned therein, and reflectors positioned in the light path from the gas discharge lamp to reflect light therefrom, which are constructed as a plurality of reflector elements of which at least one is relatively movable with respect to the light source and to another reflector element in order to permit directing light from the light source in multiple directions, in accordance with the respective orientation of the reflector elements. The structure is so arranged that an elongated lighttube or flashtube has generally parabolic reflectors surrounding the flashtube, of which one reflector element at least is relatively movable with respect to another. It is thus possible to generate light beams which can be selectively pointed in desired directions without requiring any additional optical devices, such as reflector screens and the like, or optics which form attachments to the flashgun itself. The flashgun, when constructed as an electronic flashgun, is particularly versatile since it permits, from one single flash, to obtain direct and indirect illumination, or intense direct or intense indirect illumination, in accordance with the relative orientation of the respective reflector elements with respect to the subject to be photographed, or to surrounding structures such as the ceiling of a room or studio.
The efficiency of light output obtained from the very short but intense flash of the flashtube is highly dependent not only on the quality of the reflective surfaces but also on the respective positioning of the light source with respect to the reflecting surface itself.